Field of the Invention
The invention relates to an integrated circuit, and particularly relates to a semiconductor device.
Description of Related Art
Image sensor is equipment used for converting optical images into electrical signals, and is widely applied to digital cameras and other electronic optical equipment. The early image sensor adopts an analog signal, for example a video camera tube. Today, the image sensors are mainly divided into two types of image sensors including a charge-coupled device (CCD) type and a complementary metal oxide semiconductor (CMOS) type.
The CMOS type image sensor is a device adopting a CMOS manufacturing technique to convert optical images into electrical signals. Compared with the CCD type image sensor, in the CMOS type image sensor, a signal processing circuit can be fabricated into a single chip, by which not only a product volume is reduced, it is also compatible to the CMOS technique. Therefore, the CMOS type image sensor has advantages of low manufacturing cost and low power consumption.
Generally, a light pipe structure is formed on a photo sensor to increase light sensitivity of the CMOS type image sensor. However, the light above an area outside the light pipe structure (i.e., a scattered light) is probably transmitted to the photo sensor under the light pipe structure, which may cause a cross-talk phenomenon, such that the noise received by the CMOS type image sensor is increased, and an image resolution is decreased.